I got myself a Betta a couple of days ago and it's my first fish ever.
I bought the Fluval Edge 6G. I put Gravel and some live plants in, everything got washed before. Put conditioner in as well.

But the fish started acting kinda weird after 3 days and I got worried.
He would only swim from the left to the right, over and over, and then started going crazy, looked like he used all his force to ram himself down in the gravel.

I did water-changes so the ammonia wouldn't get too high but finally decided to take him out. Now he is just in a big glass of mine until I figure out what to do next. I think about a fishless-tank-cycle checking ammonia etc. Now he does the same thing in the glass.

But please take a look at the video to let me know if that kind of behaviour is somewhat normal. Also, I think some of the skin around the gills looks scraped off, can't remember if it looked like that when I got him....

Hope he gets better soon. He's such a beauty! As for your tank I wouldnt risk it. I would take EVERYTHING out and clean it with HOT water. You might use (a little) bleach so long as you rinse very well. Otherwise you may also use aquarium salt.

I think he might have internal parasites or parasites in his gills. I don't think betta revive will help. I'm not sure what the best medication for parasites is. Maybe Bettaslave or Oldfishlady will chime in. I know bettaslave has dealt with parasites numerous times.